Sharooq

LeetCode 981: Time Based Key-Value Store Explained (Binary Search Solution)

The elegant part of this problem is recognizing that the timestamps are already sorted because of the problem constraint. The combination of: a hash map for fast key lookup, and binary search on the timestamp list gives an optimal solution

Leetcode -

Hashmaps

LeetCode 128: Longest Consecutive Sequence — Explanation

Given an integer array nums, return the length of the longest consecutive sequence that can be formed. The key trick is to only begin counting when we find the start of a sequence. This avoids repeated work and allows us to solve the problem in linear time.

Leetcode -

Hashmaps

Leetcode 36 : Valid Sudoku - Explanation

Sudoku is a classic 9×9 puzzle where each row, column, and 3×3 box must contain the digits 1 through 9 without repetition. In this problem, we are not asked to solve the Sudoku board. Instead, we only need to check whether the current board is valid.

Leetcode -

Hashmaps -

Heap

LeetCode 347: Top K Frequent Elements — Explanation

We are given an integer array nums and an integer k. We need to return the k most frequent elements in the array. Implementation using sorting, min-heap and bucket sorting are explained in this article.

Leetcode -

Hashmaps

Leetcode 49: Group Anagrams Explanation

An anagram is a word that has the same characters as another word, but possibly in a different order. For example, "act"and "cat" are anagrams because both contain the letters a, c, and t.

Leetcode -

Two Pointers -

Hashmaps

Leetcode 1: Two Sum Explained: From Brute Force to an Optimal Hash Map Solution

The Two Sum problem is one of the most popular coding interview questions. Although it looks simple, it introduces several important concepts that appear repeatedly in algorithm design, such as brute force search, sorting with two pointers, and hash maps.

Leetcode -

Hashmaps

LeetCode 217: Contains Duplicate – 4 Python Solutions Explained

One of the first array problems you’ll encounter on LeetCode is 217. Contains Duplicate. Although the problem is straightforward, it introduces an important concept: trading time for space.

Leetcode -

Hashmaps

LeetCode 242: Valid Anagram – 3 Python Solutions Explained

Valid Anagram is a classic string problem that teaches different ways to compare the frequency of characters in two strings. While the problem is simple, it introduces an important concept you’ll use repeatedly in coding interviews: counting occurrences efficiently.

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